Liquid crystal displays (LCDs) are a well known form of flat panel display. As is well known to those having skill in the art, a liquid crystal display generally includes a thin film transistor (TFT) substrate that itself includes a plurality of spaced apart gate lines and a plurality of spaced apart data lines. The plurality of spaced apart data lines intersect the plurality of spaced apart gate lines, generally orthogonally. A liquid crystal display may also generally include a color filter substrate spaced apart from the TFT substrate, and a liquid crystal material between the TFT substrate and the color filter substrate. Each intersecting area of a gate line and a data line can include a thin film transistor and a pixel electrode, to form switching devices.
The data lines receive a gray scale voltage selected by a data driving integrated circuit and transmit the gray scale voltage to the liquid crystal material. The gate lines open or close the TFT in response to signals provided from a gate driving integrated circuit. The construction and operation of an LCD are well known to those having skill in the art and need not be described further herein.
FIG. 1 is a schematic perspective view of an LCD module. As shown in FIG. 1, the LCD module includes an LCD panel 10 including the spaced apart gate lines and data lines thereon and a printed circuit board (PCB) 20 that provides signals to the data lines and/or gate lines. In order to supply the data lines and the gate lines with driving signals, a timing controller and various other integrated circuit components may be mounted on PCB 20. The PCB 20 and the LCD panel 10 are conventionally interconnected by a tape carrier package (TCP) 30 including a tape carrier 33 on which a driving integrated circuit 31 is mounted. Driving integrated circuit 31 transmits the driving signals to the gate lines and the data lines.
As shown in FIG. 1, the PCB 20 is generally a multilayer PCB. The PCB 20 and the LCD panel 10 are interconnected using the TCP 30. The pitches between the output lines 36 may be approximately 0.1 mm. An anisotropic conductive film (ACF) is attached to the respective input pads of the LCD panel 10 and the output lines 36 of the TCP 30 are heat pressed and attached to the LCD panel 10. Since the pitches between the inputs 35 of the TCP 30 and the conductive lines on the PCB 20 are wider than the input pads of the LCD panel, the TCP 30 is connected to the PCB 20 by soldering or by using an anisotropic conductive film.
Unfortunately, the use of a TCP 30 to interconnect and LCD panel 10 to a PCB 20 may increase the cost of the LCD module and/or decrease the reliability thereof. The cost may be increased because the price of a tape carrier for the TCP may be almost the same as the price of the driving IC itself. Moreover, the width of the tape carrier is standardized at 35-48 mm. Accordingly, the input and output lines of the tape carrier may be fixed according to the standardized width thereof, and the number of input and output leads to the driving IC may be limited. Accordingly, larger numbers of driving ICs may be used. Moreover, since the TCP is attached to the PCB, an additional process step may be needed. This process step may include manual intervention to align the TCP 30 to the PCB 20.
The reliability of the LCD module may also be impacted because the solid portions between the PCB and the TCP and the bonded portions between the tape carrier and the driving IC may be damaged due to differences in thermal expansion coefficients. Expansion and contraction may repeatedly occur in an LCD module due to changes in the thermal environment of a backlight unit. For example, the temperature of the backlight unit may vary over a 60.degree. range.